Abstract
In the course of this study, a series of novel, biodegradable polyanhydrides based on betulin disuccinate and dicarboxylic derivatives of poly(ethylene glycol) were prepared by two-step polycondensation. These copolymers can be used as carriers in drug delivery systems, in the form of microspheres. Betulin and its derivatives exhibit a broad spectrum of biological activity, including cytotoxic activity, which makes them promising substances for use as therapeutic agents. Microspheres that were prepared from betulin based polyanhydrides show promising properties for use in application in drug delivery systems, including inhalation systems. The obtained copolymers release the active substance—betulin disuccinate—as a result of hydrolysis under physiological conditions. The use of a poly(ethylene glycol) derivative as a co-monomer increases the solubility and bioavailability of the obtained compounds. Microspheres with diameters in the range of 0.5–25 µm were prepared by emulsion solvent evaporation method and their physicochemical and aerodynamic properties were analyzed. The morphological characteristics of the microspheres depended on the presence of poly(ethylene glycol) (PEG) segment within the structure of polyanhydrides. The porosity of the particles depended on the amount and molecular weight of the PEG used and also on the speed of homogenization. The most porous particles were obtained from polyanhydrides containing 20% wt. of PEG 600 by using a homogenization speed of 18,000 rpm.
Highlights
Introduction published maps and institutional affilIn recent years, there has been growing interest in compounds that were obtained from renewable sources
The aim of this work was the synthesis and characterization of polyanhydrides that The aim ofofthis work wasbetulin the synthesis and characterization of of polyanhydrides are are composed disuccinate and dicarboxylic derivatives poly(ethylene that glycol), composed of disuccinate betulin and dicarboxylic derivatives of poly(ethylene glycol), and and the creation of microspheres from those materials, which could be used as drug carthe of microspheres from those materials, could be as drugand carriers rierscreation in controlled drug delivery systems
The results shows that the cytostatic activity of the polyanhydrides based on betulin disuccinate can be manipulated by changing the kind of comonomer and its content, allowing for an optimization of the degradation rate and, a its content, allowing for an optimization ofon thethe degradation rate and, tailored period tailored period of cytotoxicity, depending specific application
Summary
Introduction published maps and institutional affilIn recent years, there has been growing interest in compounds that were obtained from renewable sources. Studies are being carried out on the isolation of substances from plant extracts that may be usable in, among others, cosmetics and pharmaceutical industries Such compounds can be used directly as ingredients of preparations, but they may be subjected to various modifications in order to obtain new compounds, including polymers. Modification of the structure of betulin in C-3 and C-28 positions makes it possible to obtain derivatives with anti-inflammatory [2], anti-viral [3], and anti-cancer activity [1]. Thanks to those properties, the modified compounds are promising as new therapeutic agents. There are only several literature reports describing the polymeric forms of betulin, including polyesters [4], iations
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